Line data    Source code

       1             : /* SPDX-License-Identifier: GPL-2.0-only */
       2             : /*
       3             :  * Access to user system call parameters and results
       4             :  *
       5             :  * Copyright (C) 2008-2009 Red Hat, Inc.  All rights reserved.
       6             :  *
       7             :  * See asm-generic/syscall.h for descriptions of what we must do here.
       8             :  */
       9             : 
      10             : #ifndef _ASM_X86_SYSCALL_H
      11             : #define _ASM_X86_SYSCALL_H
      12             : 
      13             : #include <uapi/linux/audit.h>
      14             : #include <linux/sched.h>
      15             : #include <linux/err.h>
      16             : #include <asm/thread_info.h>      /* for TS_COMPAT */
      17             : #include <asm/unistd.h>
      18             : 
      19             : typedef long (*sys_call_ptr_t)(const struct pt_regs *);
      20             : extern const sys_call_ptr_t sys_call_table[];
      21             : 
      22             : #if defined(CONFIG_X86_32)
      23             : #define ia32_sys_call_table sys_call_table
      24             : #endif
      25             : 
      26             : #if defined(CONFIG_IA32_EMULATION)
      27             : extern const sys_call_ptr_t ia32_sys_call_table[];
      28             : #endif
      29             : 
      30             : #ifdef CONFIG_X86_X32_ABI
      31             : extern const sys_call_ptr_t x32_sys_call_table[];
      32             : #endif
      33             : 
      34             : /*
      35             :  * Only the low 32 bits of orig_ax are meaningful, so we return int.
      36             :  * This importantly ignores the high bits on 64-bit, so comparisons
      37             :  * sign-extend the low 32 bits.
      38             :  */
      39      297236 : static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
      40             : {
      41      297236 :         return regs->orig_ax;
      42             : }
      43             : 
      44           0 : static inline void syscall_rollback(struct task_struct *task,
      45             :                                     struct pt_regs *regs)
      46             : {
      47           0 :         regs->ax = regs->orig_ax;
      48             : }
      49             : 
      50        1284 : static inline long syscall_get_error(struct task_struct *task,
      51             :                                      struct pt_regs *regs)
      52             : {
      53        1284 :         unsigned long error = regs->ax;
      54             : #ifdef CONFIG_IA32_EMULATION
      55             :         /*
      56             :          * TS_COMPAT is set for 32-bit syscall entries and then
      57             :          * remains set until we return to user mode.
      58             :          */
      59        1284 :         if (task->thread_info.status & (TS_COMPAT|TS_I386_REGS_POKED))
      60             :                 /*
      61             :                  * Sign-extend the value so (int)-EFOO becomes (long)-EFOO
      62             :                  * and will match correctly in comparisons.
      63             :                  */
      64           0 :                 error = (long) (int) error;
      65             : #endif
      66        1284 :         return IS_ERR_VALUE(error) ? error : 0;
      67             : }
      68             : 
      69           0 : static inline long syscall_get_return_value(struct task_struct *task,
      70             :                                             struct pt_regs *regs)
      71             : {
      72           0 :         return regs->ax;
      73             : }
      74             : 
      75             : static inline void syscall_set_return_value(struct task_struct *task,
      76             :                                             struct pt_regs *regs,
      77             :                                             int error, long val)
      78             : {
      79             :         regs->ax = (long) error ?: val;
      80             : }
      81             : 
      82             : #ifdef CONFIG_X86_32
      83             : 
      84             : static inline void syscall_get_arguments(struct task_struct *task,
      85             :                                          struct pt_regs *regs,
      86             :                                          unsigned long *args)
      87             : {
      88             :         memcpy(args, &regs->bx, 6 * sizeof(args[0]));
      89             : }
      90             : 
      91             : static inline void syscall_set_arguments(struct task_struct *task,
      92             :                                          struct pt_regs *regs,
      93             :                                          unsigned int i, unsigned int n,
      94             :                                          const unsigned long *args)
      95             : {
      96             :         BUG_ON(i + n > 6);
      97             :         memcpy(&regs->bx + i, args, n * sizeof(args[0]));
      98             : }
      99             : 
     100             : static inline int syscall_get_arch(struct task_struct *task)
     101             : {
     102             :         return AUDIT_ARCH_I386;
     103             : }
     104             : 
     105             : #else    /* CONFIG_X86_64 */
     106             : 
     107           0 : static inline void syscall_get_arguments(struct task_struct *task,
     108             :                                          struct pt_regs *regs,
     109             :                                          unsigned long *args)
     110             : {
     111             : # ifdef CONFIG_IA32_EMULATION
     112           0 :         if (task->thread_info.status & TS_COMPAT) {
     113           0 :                 *args++ = regs->bx;
     114           0 :                 *args++ = regs->cx;
     115           0 :                 *args++ = regs->dx;
     116           0 :                 *args++ = regs->si;
     117           0 :                 *args++ = regs->di;
     118           0 :                 *args   = regs->bp;
     119             :         } else
     120             : # endif
     121             :         {
     122           0 :                 *args++ = regs->di;
     123           0 :                 *args++ = regs->si;
     124           0 :                 *args++ = regs->dx;
     125           0 :                 *args++ = regs->r10;
     126           0 :                 *args++ = regs->r8;
     127           0 :                 *args   = regs->r9;
     128             :         }
     129           0 : }
     130             : 
     131             : static inline void syscall_set_arguments(struct task_struct *task,
     132             :                                          struct pt_regs *regs,
     133             :                                          const unsigned long *args)
     134             : {
     135             : # ifdef CONFIG_IA32_EMULATION
     136             :         if (task->thread_info.status & TS_COMPAT) {
     137             :                 regs->bx = *args++;
     138             :                 regs->cx = *args++;
     139             :                 regs->dx = *args++;
     140             :                 regs->si = *args++;
     141             :                 regs->di = *args++;
     142             :                 regs->bp = *args;
     143             :         } else
     144             : # endif
     145             :         {
     146             :                 regs->di = *args++;
     147             :                 regs->si = *args++;
     148             :                 regs->dx = *args++;
     149             :                 regs->r10 = *args++;
     150             :                 regs->r8 = *args++;
     151             :                 regs->r9 = *args;
     152             :         }
     153             : }
     154             : 
     155           0 : static inline int syscall_get_arch(struct task_struct *task)
     156             : {
     157             :         /* x32 tasks should be considered AUDIT_ARCH_X86_64. */
     158           0 :         return (IS_ENABLED(CONFIG_IA32_EMULATION) &&
     159           0 :                 task->thread_info.status & TS_COMPAT)
     160           0 :                 ? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64;
     161             : }
     162             : 
     163             : void do_syscall_64(unsigned long nr, struct pt_regs *regs);
     164             : void do_int80_syscall_32(struct pt_regs *regs);
     165             : long do_fast_syscall_32(struct pt_regs *regs);
     166             : 
     167             : #endif  /* CONFIG_X86_32 */
     168             : 
     169             : #endif  /* _ASM_X86_SYSCALL_H */